JP2015010174A - Cleaner for molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure cleaning force of a cleaner and enhance self discharge ability, because a resin or an additive which was used previously remains on a device, defect occurs, so that a cleaner is put thereinto after completion of molding for discharging a resin remaining on the device, and the cleaner itself is discharged by following resin molding, in which the resin and the additive are efficiently put thereinto alternately.SOLUTION: An inorganic material of 20-120 pts.mass, a fluoro-resin of 0.3-3 pts.mass, and PEG or PEO of 1-5 pts.mass are included with respect to a thermoplastic resin of 100 pts.mass for forming a cleaner for molding machine.

Description

  The present invention relates to a molding machine cleaning agent for efficiently performing color change and resin change in a molding machine that melts and molds a thermoplastic resin or rubber material such as an injection molding machine.

  In a molding machine that melts a thermoplastic resin or rubber material at a high temperature, such as an injection molding machine or an extruder, and kneads and molds it with an additive such as a colorant, a resin other than the resin used for the previous molding, addition When the next molding is continuously performed using the agent, if the previous material remains in the apparatus, problems such as deterioration of physical properties due to contamination or the like and poor appearance appear in the subsequent molded product.

  Originally, it is preferable to remove the screw from the molding machine after the molding is completed, and to completely clean the inside of the cylinder of the molding machine and the screw. However, this process is time consuming and expensive. Normally, the next resin is used to flow the previous resin, but some colorants and additives can easily remain in the molding machine. If the time for switching this molding material is improved, the work efficiency increases and the cost increases. Can be suppressed.

  Therefore, in the conventional molding, after the previous molding is completed, the cleaning agent is flown and the previous resin is strongly discharged, and the cleaning agent itself is quickly discharged by the subsequent resin, so that the switching of the resin and additives can be performed efficiently. Do.

  Many of the conventional cleaners for molding machines have PP resin or AS resin as the base resin and glass fiber as the main component. As a glass fiber cleaning effect, it has the effect of scraping resin stuck inside the molding machine from its shape. On the other hand, the glass fiber has an adhesion property that it is easily caught inside the molding machine and easily remains inside the molding machine. In addition to glass fibers, other conventional technologies include inorganic substances with limited sizes (Patent Document 1), higher fatty acids and borate ester anionic surfactants (Patent Document 2), polyhydric alcohols and alkylene glycol fatty acid esters, fatty acid metals Many patents have already been made, such as blending (Patent Document 3), styrene-based thermoplastic elastomer and ultra-high polymer (Patent Document 4), fluorine-based resin and wollastonite (Patent Document 5).

JP-A-5-295397 JP-A-8-59905 JP 2000-119458 A Japanese Patent Laid-Open No. 2001-348600 JP 2004-107433 A

  Numerous developments have been made to improve the cleaning power of molding machine cleaners. However, there is little development regarding the subsequent discharge of cleaning agents. Even if the detergency is high, the use of a cleaning agent is lost if it takes a lot of time to replace the resin used in the next operation.

  The subject of this invention is providing the cleaning agent for molding machines which improved self-discharge property, ensuring the cleaning power.

  The present invention is a cleaning agent for a washing machine containing 20 to 120 parts by weight of an inorganic substance, 0.3 to 3 parts by weight of a fluororesin, and 1 to 5 parts by weight of PEG or PEO with respect to 100 parts by weight of a thermoplastic resin. .

  Examples of the base thermoplastic resin include polypropylene resin (PP) and acrylonitrile-styrene copolymer (AS). In this study, the melt flow rate of thermoplastic resin is 1-15g / 10min (220 ℃ ・ 10kg) (220 ℃ is material melting temperature, 10kg is material extrusion load).

  Examples of the fluorine-based resin include polytetrafluoroethylene resin (PTFE) and ethylene-polytetrafluoroethylene copolymer (ETFE). In general, those containing fluorine have poor adhesion to other raw materials, and are often modified to improve adhesion. The present invention is characterized in that a normal fluororesin is used without modification.

  Polyethylene glycol (PEG) and polyethylene oxide (PEO) have the same structure, but the original difference is whether the starting ethylene glycol is produced by dehydration condensation or ethylene oxide ring-opening polymerization. Generally distinguished by molecular weight. In other words, those with a molecular weight of 50,000 or less are PEG, and those with a molecular weight of 50,000 or more are PEO. The present invention is characterized in that the molecular weight of PEG or PEO is 10,000 or more.

  Examples of inorganic substances added to the resin cleaner include glass fiber and calcium carbonate. In addition, the same effect can be obtained with wollastonite or glass beads. However, the inorganic substance to be used must have sufficiently improved adhesion to the base resin. In the case of ordinary glass fiber, the surface of the fiber is improved with a surface modifier or the like, and sufficient adhesion to the molten resin is exhibited. If the adhesiveness is not sufficient, the inorganic substance tends to remain in the apparatus during cleaning, and the self-discharge property is reduced.

  In the present invention, the reason why the cleaning is particularly ensured and the self-discharge property is enhanced will be described below.

  The reason for setting the melt rate of the thermoplastic resin as the base in the cleaning agent to 1 to 15 g / 10 min (220 ° C, 10 kg) is that the lower the melt flow rate, the greater the pressure in the molding machine and the more dirty Can be dropped. Further, when the melt flow rate is lowered, mass productivity is significantly lowered when the detergent is kneaded and pelletized with an extruder. Therefore, the melt flow rate of the thermoplastic resin which is the base of the cleaning agent needs to have the above-mentioned appropriate value.

  The reason why the inorganic substance is 20 to 120 parts by weight with respect to 100 parts by weight of the thermoplastic resin is to ensure a cleaning effect and mass productivity. If the inorganic substance is less than 20 parts by weight, the removal ability to the inner wall of the molding machine is insufficient, and the expected cleaning effect is not improved. If it exceeds 120 parts by weight, it is not practical because mass productivity such as a decrease in the production amount of the detergent pellets is reduced.

  The reason why fluorine-based resins are used in combination with inorganic substances in cleaning agents is that when inorganic substances adhere strongly to the thermoplastic resin that constitutes the cleaning agent to form a resin mass as a whole, high melting based on fluorine of fluorine-based resins The tension strengthens the entire mass of the resin mass and contributes to the resin mass being collectively discharged out of the molding machine, thereby improving the replacement property of the thermoplastic resin, that is, the self-discharge property. At this time, the fluorine resin is not a modified fluorine resin but an unmodified fluorine resin. This is to prevent a decrease in the proportion of fluorine in the whole when the fluororesin is modified, and to avoid a decrease in its melt tension. The reason why the fluorine resin content is 0.3 to 3 parts by weight is that if it is less than 0.3 parts by weight, it does not contribute to the self-discharge property of the thermoplastic resin, and if it exceeds 3 parts by weight, the self-discharge property of the thermoplastic resin is improved. Because it does not.

  As an inorganic substance contained in the cleaning agent, glass fiber or calcium carbonate can be used.

  When the glass fiber is surface-treated with a sizing agent and has activity, the glass fiber is preferable because it has low adhesion to a screw in the molding machine.

  The calcium carbonate preferably has a particle size of 10 μm or more and 80 μm or less. The reason why the particle size of calcium carbonate is 10 μm or more and 80 μm or less in the cleaning agent is that the above particle size constitutes a undulating form suitable for the cleaning effect in the pulverization method in the production process of general calcium carbonate powder. In addition, the addition to the thermoplastic resin is easy. In general, the calcium carbonate powder is manufactured by mining and then mineralizing and grinding. At this time, as the powder is pulverized for a long time or strongly, the particle size is reduced from the rock-like lump, and the shape is also smoothed and pulverized into a spherical shape. In the case of washing of the molding machine, the undulating inorganic material such as fiber or plate has a higher washing effect than the spherical shape. That is, although depending on the production method, the calcium carbonate produced by pulverization has a higher cleaning effect in the non-spherical shape having a particle size of 10 μm or more. However, when the particle diameter exceeds 80 μm, it is difficult to disperse by kneading in an extruder, and mass productivity such as a decrease in production volume is lowered, which is not practical.

  However, calcium carbonate having a particle size of less than 10 μm is preferable in that the particle shape becomes spherical and becomes active, and the adhesion to a screw or the like in the molding machine becomes weak.

  The reason for using PEG or PEO in the cleaning agent is to reduce the metal adhesion of the thermoplastic resin to the inner surface of the molding machine and to improve the self-discharge property of mold release of the thermoplastic resin. In general, when a thermoplastic resin having a molecular weight lower than the average molecular weight is added, the melt viscosity becomes low, and when a thermoplastic resin having a molecular weight higher than the average molecular weight is added, the melt viscosity becomes high. This is the same when PEG or PEO is added to the thermoplastic resin. If the molecular weight of PEG or PEO is 10,000 or more, the thermoplastic resin has the same or higher melt viscosity, the detergency is increased, and the molecular weight is increased. If it is low, the melt viscosity is lowered and the cleaning power is lowered. On the other hand, when the melt viscosity of the thermoplastic resin is lowered, the fluidity is increased, so that the self-discharge property is improved. At this time, when the thermoplastic resin is used in combination with an inorganic substance that adds high detergency, such as glass fiber, PEG that gives a relatively low molecular weight and lowers the melt viscosity of the thermoplastic resin is prioritized to improve self-discharge. When using an inorganic material that does not have a high detergency, such as charcoal cal, it is effective to use PEO that has a relatively high molecular weight and increases the melt viscosity of the thermoplastic resin in order to improve detergency. . That is, PEG or PEO is selected depending on the inorganic substance used in combination with the thermoplastic resin. PEG or PEO also softens the hard molding material used in the previous molding, makes it possible to easily extrude the molding material used in the previous molding, and improves the cleanability. The reason why the content of PEG or PEO is 1 to 5 parts by weight is that if it is less than 1 part by weight, it does not contribute to the self-discharge property of the thermoplastic resin. This is because the discharge performance is not improved.

As the AS resin, SAN-H (manufactured by Techno Polymer Co., Ltd.) was used. 050SF (manufactured by Daicel Polymer Co., Ltd.) was used as the low viscosity AS resin. MH4 (manufactured by Nippon Polypro) was used as the PP resin. As the glass fiber (GF), ECS304A (manufactured by CPIC) was used. As calcium carbonate (CaCO ₃ ), NN-200 (average particle size 14.8 μm, manufactured by Nitto Flour Chemical Co., Ltd.) was used. SS-80 (average particle size: 2 μm, manufactured by Nitto Flour Chemical Co., Ltd.) was used as the small particle size calcium carbonate. Alcox L-11 (molecular weight 110,000: manufactured by Meisei Chemical Industry Co., Ltd.) was used for PEO. As the PEG, 20000P (molecular weight 20,000: manufactured by Sanyo Kasei Co., Ltd.) was used. The low molecular weight PEG used was 4000 N (molecular weight 3,000: manufactured by Sanyo Chemical Co., Ltd.). R-88AX (Asahi Glass Co., Ltd.) was used as ETFE. A3000 (manufactured by Mitsubishi Rayon Co., Ltd.) was used as a modified ETFE. C-300 (Asahi Glass Co., Ltd.) was used as PTFE. The MFR in Table 1 shows the result of the melt flow rate of the base resin alone at 220 ° C. and 10 kg, and the unit is g / 10 min.

  The composition shown in Table 1 was melt-kneaded with a twin-screw extruder to obtain a pellet-shaped cleaning composition. These compositions were tested for cleaning performance and self-discharge performance by the following methods.

  An injection molding machine (CN-30 NIIGATA) was used as a test machine. The cylinder temperature shown in Table 1 (220 ° C or 280 ° C) is set, and the black colored resin of PP or PC (polycarbonate resin) shown in Table 1 is allowed to flow into the molding machine. The black colored resin was filled in the molding machine for 5 minutes, and then the screw was rotated to discharge the black colored resin from the molding machine. Thereafter, the cleaning agent is poured into the molding machine, and the weight (unit: g) of the cleaning agent is measured until the color of the black colored resin attached to the cleaning agent disappears. The weight was used as an index of cleaning performance. The results are shown in Table 1.

  Regarding the self-discharge performance, after the above, the screw is rotated and excess cleaning agent is poured out. Thereafter, the cylinder temperature shown in Table 1 (220 ° C.) is set, the GPPS (general-purpose polystyrene resin) shown in Table 1 is passed, and the weight (unit: g) of the cleaning agent passed until the foreign substance disappears is clear. . The weight was used as an index of self-discharge performance. The results are shown in Table 1.

Example 1
As cleaning agents, 100 parts by weight of AS resin (base resin) with 7 g / 10 min metal flow rate, 115 parts by weight of GF (inorganic) surface-treated with a sizing agent, and 2 parts by weight of PEG with a molecular weight of 20,000 (added) Product) and 1 part by weight of PTFE (fluorine resin) were kneaded and mixed.
It was confirmed that both the cleaning performance and the self-discharge performance were good.

(Comparative Example 1)
Compared with the cleaning agent of Example 1, one containing no PEG and PTFE was used.
Deterioration of self-discharge performance was observed.

(Comparative Example 2)
Compared with the cleaning agent of Example 1, a fluororesin containing 1 part by weight of modified ETFE instead of PTFE was used.
Deterioration of self-discharge performance was observed.

(Comparative Example 3)
Compared with the cleaning agent of Example 1, an additive containing 2 parts by weight of low molecular weight PEG having a molecular weight of 3000 was used instead of PEG.
Deterioration of cleaning performance and self-discharge performance was observed.

(Example 2)
Compared with the cleaning agent of Example 1, 37 parts by weight of CaCO ₃ is used as an inorganic substance instead of GF, 3 parts by weight of PEO having a molecular weight of 110,000 is contained as an additive, and PTFE is used as a fluororesin. Instead of, one containing 1 part by weight of ETFE was used.
It was confirmed that both the cleaning performance and the self-discharge performance were good.

Example 3
As compared with the cleaning agent of Example 2, a fluororesin containing 1 part by weight of PTFE instead of ETFE was used.
It was confirmed that both the cleaning performance and the self-discharge performance were good.

(Comparative Example 4)
Compared with the cleaning agent of Example 2, the one not containing PEO and ETFE was used.
Deterioration of cleaning performance and self-discharge performance was observed.

(Comparative Example 5)
The AS resin metal flow rate was 32 g / 10 min as compared with the cleaning agent of Example 2.
Deterioration of cleaning performance and self-discharge performance was observed.

(Comparative Example 6)
Than the cleaning agent in Example 2, it was used which contain small particle size CaCO ₃ 37 parts by weight instead of CaCO ₃ as inorganic.
Deterioration of cleaning performance and self-discharge performance was observed.

Example 4
100 parts by weight of PP resin (base resin) with a metal flow rate of 5 g / 10 min as a cleaning agent, and CaCO ₃
A mixture obtained by kneading and mixing 76 parts by weight (inorganic substance), 4 parts by weight of PEO having a molecular weight of 110,000 (additive), and 1 part by weight of PTFE (fluorine resin) was used.
It was confirmed that both the cleaning performance and the self-discharge performance were good.

(Example 5)
Compared with the cleaning agent of Example 4, an inorganic material containing 37 parts by weight of CaCO ₃ was used.
It was confirmed that both the cleaning performance and the self-discharge performance were good.

(Comparative Example 7)
Compared with the cleaning agent of Example 4, an inorganic material containing 15 parts by weight of CaCO ₃ was used.
Deterioration in cleaning performance was observed.

  The present invention relates to a cleaning agent for a molding machine containing 20 to 120 parts by weight of an inorganic substance, 0.3 to 3 parts by weight of a fluororesin, and 1 to 5 parts by weight of PEG or PEO with respect to 100 parts by weight of a thermoplastic resin. It was. Thereby, self-discharge property can be improved, ensuring a cleaning power.

Claims (6)

  A cleaning agent for a molding machine comprising 20 to 120 parts by weight of an inorganic substance, 0.3 to 3 parts by weight of a fluororesin, and 1 to 5 parts by weight of PEG or PEO with respect to 100 parts by weight of a thermoplastic resin.   2. The molding machine cleaning agent according to claim 1, wherein the thermoplastic resin has a melt flow rate of 1 to 15 g / 10 min (220 ° C. · 10 kg).   The cleaning agent for a molding machine according to claim 1 or 2, wherein the inorganic substance is glass fiber or calcium carbonate.   The cleaning agent for a molding machine according to any one of claims 1 to 3, wherein the fluororesin is PTFE or ETFE.   The cleaning agent for molding machines according to any one of claims 1 to 4, wherein PEG or PEO has a molecular weight of 10,000 or more.   The cleaning agent for a molding machine according to any one of claims 1 to 5, wherein the particle size of calcium carbonate is 10 µm or more and 80 µm or less.